1.5 The Theory of Plate Tectonics



Vocabulary


Plates-the lithosphere broken into separate sections
Scienctific theory- a well tested concept that explains a wide range of observations
Plate tectonics- a geological theory that states that pieces of Earth's lithosphere are in constant,
slow motion, driven by convection currents in the mantle

Faults- breaks in the Earth's crust where rocks have slipped past each other
Transform boundary- a place where two plates slip past each other,moving in opposite directions
Divergent boundary- a place where two plates move apart
Convergent boundary- a place where two plates come together
Rift Valley- a deep valley that forms where two plates move apart


Outline



Introduction


  • 1965 J. Tuzo Wilson
    • Wilson thought the lithosphere was broken into pieces
      • pieces called plates.
  • the plates fit closely together

Theory of Plate Motion


  • formation
  • movement
  • subduction

Plate Boundaries


  • Transform boundary
  • Divergent boundary
  • Convergent boundary



Transform Boundaries


  • Earthquakes occur frequently along these boundaries

Divergent Boundaries


  • Occur along the mid-ocean ridge
    • Also occur on land
      • Rift valleys occur near divergent boundaries

Convergent Boundaries


  • When 2 plates converge, they cause a collision
  • Oceanic crust and oceanic crust
  • Continental crust and oceanic crust
  • Continental crust and continental crust
    • Density desides which plate comes on top
      • Can create mountains



The Continent's Slow Dance


  • plates move at amazingly slow rates
    • 1-10 centimeters per year!
      • that's how fast your fingernails grow!